1SYSTEMD.TIME(7)                  systemd.time                  SYSTEMD.TIME(7)
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NAME

6       systemd.time - Time and date specifications
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DESCRIPTION

9       In systemd, timestamps, time spans, and calendar events are displayed
10       and may be specified in closely related syntaxes.
11

DISPLAYING TIME SPANS

13       Time spans refer to time durations. On display, systemd will present
14       time spans as a space-separated series of time values each suffixed by
15       a time unit. Example:
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17           2h 30min
18
19       All specified time values are meant to be added up. The above hence
20       refers to 150 minutes. Display is locale-independent, only English
21       names for the time units are used.
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PARSING TIME SPANS

24       When parsing, systemd will accept the same time span syntax. Separating
25       spaces may be omitted. The following time units are understood:
26
27       ·   usec, us, µs
28
29       ·   msec, ms
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31       ·   seconds, second, sec, s
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33       ·   minutes, minute, min, m
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35       ·   hours, hour, hr, h
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37       ·   days, day, d
38
39       ·   weeks, week, w
40
41       ·   months, month, M (defined as 30.44 days)
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43       ·   years, year, y (defined as 365.25 days)
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45       If no time unit is specified, generally seconds are assumed, but some
46       exceptions exist and are marked as such. In a few cases "ns", "nsec" is
47       accepted too, where the granularity of the time span permits this.
48       Parsing is generally locale-independent, non-English names for the time
49       units are not accepted.
50
51       Examples for valid time span specifications:
52
53           2 h
54           2hours
55           48hr
56           1y 12month
57           55s500ms
58           300ms20s 5day
59
60       One can use the timespan command of systemd-analyze(1) to normalise a
61       textual time span for testing and validation purposes.
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DISPLAYING TIMESTAMPS

64       Timestamps refer to specific, unique points in time. On display,
65       systemd will format these in the local timezone as follows:
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67           Fri 2012-11-23 23:02:15 CET
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69       The weekday is printed in the abbreviated English language form. The
70       formatting is locale-independent.
71
72       In some cases timestamps are shown in the UTC timezone instead of the
73       local timezone, which is indicated via the "UTC" timezone specifier in
74       the output.
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76       In some cases timestamps are shown with microsecond granularity. In
77       this case the sub-second remainder is separated by a full stop from the
78       seconds component.
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PARSING TIMESTAMPS

81       When parsing, systemd will accept a similar syntax, but expects no
82       timezone specification, unless it is given as the literal string "UTC"
83       (for the UTC timezone), or is specified to be the locally configured
84       timezone, or the timezone name in the IANA timezone database format.
85       The complete list of timezones supported on your system can be obtained
86       using the "timedatectl list-timezones" (see timedatectl(1)). Using IANA
87       format is recommended over local timezone names, as less prone to
88       errors (eg: with local timezone it's possible to specify daylight
89       saving time in winter, while it's incorrect). The weekday specification
90       is optional, but when the weekday is specified, it must either be in
91       the abbreviated ("Wed") or non-abbreviated ("Wednesday") English
92       language form (case does not matter), and is not subject to the locale
93       choice of the user. Either the date, or the time part may be omitted,
94       in which case the current date or 00:00:00, respectively, is assumed.
95       The seconds component of the time may also be omitted, in which case
96       ":00" is assumed. Year numbers may be specified in full or may be
97       abbreviated (omitting the century).
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99       A timestamp is considered invalid if a weekday is specified and the
100       date does not match the specified day of the week.
101
102       When parsing, systemd will also accept a few special placeholders
103       instead of timestamps: "now" may be used to refer to the current time
104       (or of the invocation of the command that is currently executed).
105       "today", "yesterday", and "tomorrow" refer to 00:00:00 of the current
106       day, the day before, or the next day, respectively.
107
108       When parsing, systemd will also accept relative time specifications. A
109       time span (see above) that is prefixed with "+" is evaluated to the
110       current time plus the specified time span. Correspondingly, a time span
111       that is prefixed with "-" is evaluated to the current time minus the
112       specified time span. Instead of prefixing the time span with "+" or
113       "-", it may also be suffixed with a space and the word "left" or "ago".
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115       Finally, a timespan prefixed with "@" is evaluated relative to the UNIX
116       time epoch 1st Jan, 1970, 00:00.
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118       Examples for valid timestamps and their normalized form (assuming the
119       current time was 2012-11-23 18:15:22 and the timezone was UTC+8, for
120       example TZ=Asia/Shanghai):
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122             Fri 2012-11-23 11:12:13 → Fri 2012-11-23 11:12:13
123                 2012-11-23 11:12:13 → Fri 2012-11-23 11:12:13
124             2012-11-23 11:12:13 UTC → Fri 2012-11-23 19:12:13
125                          2012-11-23 → Fri 2012-11-23 00:00:00
126                            12-11-23 → Fri 2012-11-23 00:00:00
127                            11:12:13 → Fri 2012-11-23 11:12:13
128                               11:12 → Fri 2012-11-23 11:12:00
129                                 now → Fri 2012-11-23 18:15:22
130                               today → Fri 2012-11-23 00:00:00
131                           today UTC → Fri 2012-11-23 16:00:00
132                           yesterday → Fri 2012-11-22 00:00:00
133                            tomorrow → Fri 2012-11-24 00:00:00
134           tomorrow Pacific/Auckland → Thu 2012-11-23 19:00:00
135                            +3h30min → Fri 2012-11-23 21:45:22
136                                 -5s → Fri 2012-11-23 18:15:17
137                           11min ago → Fri 2012-11-23 18:04:22
138                         @1395716396 → Tue 2014-03-25 03:59:56
139
140       Note that timestamps displayed by remote systems with a non-matching
141       timezone are usually not parsable locally, as the timezone component is
142       not understood (unless it happens to be "UTC").
143
144       Timestamps may also be specified with microsecond granularity. The
145       sub-second remainder is expected separated by a full stop from the
146       seconds component. Example:
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148           2014-03-25 03:59:56.654563
149
150       In some cases, systemd will display a relative timestamp (relative to
151       the current time, or the time of invocation of the command) instead of
152       or in addition to an absolute timestamp as described above. A relative
153       timestamp is formatted as follows:
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155           2 months 5 days ago
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157       Note that a relative timestamp is also accepted where a timestamp is
158       expected (see above).
159
160       Use the timestamp command of systemd-analyze(1) to validate and
161       normalize timestamps for testing purposes.
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CALENDAR EVENTS

164       Calendar events may be used to refer to one or more points in time in a
165       single expression. They form a superset of the absolute timestamps
166       explained above:
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168           Thu,Fri 2012-*-1,5 11:12:13
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170       The above refers to 11:12:13 of the first or fifth day of any month of
171       the year 2012, but only if that day is a Thursday or Friday.
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173       The weekday specification is optional. If specified, it should consist
174       of one or more English language weekday names, either in the
175       abbreviated (Wed) or non-abbreviated (Wednesday) form (case does not
176       matter), separated by commas. Specifying two weekdays separated by ".."
177       refers to a range of continuous weekdays.  "," and ".."  may be
178       combined freely.
179
180       In the date and time specifications, any component may be specified as
181       "*" in which case any value will match. Alternatively, each component
182       can be specified as a list of values separated by commas. Values may be
183       suffixed with "/" and a repetition value, which indicates that the
184       value itself and the value plus all multiples of the repetition value
185       are matched. Two values separated by ".."  may be used to indicate a
186       range of values; ranges may also be followed with "/" and a repetition
187       value.
188
189       A date specification may use "~" to indicate the last day(s) in a
190       month. For example, "*-02~03" means "the third last day in February,"
191       and "Mon *-05~07/1" means "the last Monday in May."
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193       The seconds component may contain decimal fractions both in the value
194       and the repetition. All fractions are rounded to 6 decimal places.
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196       Either time or date specification may be omitted, in which case the
197       current day and 00:00:00 is implied, respectively. If the second
198       component is not specified, ":00" is assumed.
199
200       Timezone can be specified as the literal string "UTC", or the local
201       timezone, similar to the supported syntax of timestamps (see above), or
202       the timezone in the IANA timezone database format (also see above).
203
204       The following special expressions may be used as shorthands for longer
205       normalized forms:
206
207               minutely → *-*-* *:*:00
208                 hourly → *-*-* *:00:00
209                  daily → *-*-* 00:00:00
210                monthly → *-*-01 00:00:00
211                 weekly → Mon *-*-* 00:00:00
212                 yearly → *-01-01 00:00:00
213              quarterly → *-01,04,07,10-01 00:00:00
214           semiannually → *-01,07-01 00:00:00
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216
217       Examples for valid timestamps and their normalized form:
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219             Sat,Thu,Mon..Wed,Sat..Sun → Mon..Thu,Sat,Sun *-*-* 00:00:00
220                 Mon,Sun 12-*-* 2,1:23 → Mon,Sun 2012-*-* 01,02:23:00
221                               Wed *-1 → Wed *-*-01 00:00:00
222                      Wed..Wed,Wed *-1 → Wed *-*-01 00:00:00
223                            Wed, 17:48 → Wed *-*-* 17:48:00
224           Wed..Sat,Tue 12-10-15 1:2:3 → Tue..Sat 2012-10-15 01:02:03
225                           *-*-7 0:0:0 → *-*-07 00:00:00
226                                 10-15 → *-10-15 00:00:00
227                   monday *-12-* 17:00 → Mon *-12-* 17:00:00
228             Mon,Fri *-*-3,1,2 *:30:45 → Mon,Fri *-*-01,02,03 *:30:45
229                  12,14,13,12:20,10,30 → *-*-* 12,13,14:10,20,30:00
230                       12..14:10,20,30 → *-*-* 12..14:10,20,30:00
231             mon,fri *-1/2-1,3 *:30:45 → Mon,Fri *-01/2-01,03 *:30:45
232                        03-05 08:05:40 → *-03-05 08:05:40
233                              08:05:40 → *-*-* 08:05:40
234                                 05:40 → *-*-* 05:40:00
235                Sat,Sun 12-05 08:05:40 → Sat,Sun *-12-05 08:05:40
236                      Sat,Sun 08:05:40 → Sat,Sun *-*-* 08:05:40
237                      2003-03-05 05:40 → 2003-03-05 05:40:00
238            05:40:23.4200004/3.1700005 → *-*-* 05:40:23.420000/3.170001
239                        2003-02..04-05 → 2003-02..04-05 00:00:00
240                  2003-03-05 05:40 UTC → 2003-03-05 05:40:00 UTC
241                            2003-03-05 → 2003-03-05 00:00:00
242                                 03-05 → *-03-05 00:00:00
243                                hourly → *-*-* *:00:00
244                                 daily → *-*-* 00:00:00
245                             daily UTC → *-*-* 00:00:00 UTC
246                               monthly → *-*-01 00:00:00
247                                weekly → Mon *-*-* 00:00:00
248               weekly Pacific/Auckland → Mon *-*-* 00:00:00 Pacific/Auckland
249                                yearly → *-01-01 00:00:00
250                              annually → *-01-01 00:00:00
251                                 *:2/3 → *-*-* *:02/3:00
252
253       Calendar events are used by timer units, see systemd.timer(5) for
254       details.
255
256       Use the calendar command of systemd-analyze(1) to validate and
257       normalize calendar time specifications for testing purposes. The tool
258       also calculates when a specified calendar event would elapse next.
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SEE ALSO

261       systemd(1), journalctl(1), systemd.timer(5), systemd.unit(5),
262       systemd.directives(7), systemd-analyze(1)
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266systemd 243                                                    SYSTEMD.TIME(7)
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